In general, multi-function tools, including in a single instrument, pliers, and other selected tools, such as screwdrivers, knife blades, files, scissors and the like are well known. The prior art tools typically include a cross-jaw pliers with channel-shaped handles pivotally connected to the shanks (tangs) of the respective plier jaws. The handles fold over the pliers so that the pliers are received in the handle channels. Respective tools, channel-shaped handle extensions, or both, are pivotally mounted to each handle at the distal end, adapted to fall into the handle channel or nest within the handle, respectively, for storage. Examples of such multiple tools are described in U.S. Pat. Nos. 4,238,862, 4,744,272, and 4,888,869, issued on Dec. 16, 1980, May 17, 1988, and Dec. 26, 1989, respectively, to Timothy S. Leatherman, and U.S. Pat. No. 5,062,173 issued Nov. 5, 1991 to Collins.
The tools disclosed in the Leatherman patents are disadvantageous in that the use of both hands is required to unfold the handles from the nested storage position to expose the plier jaws. Likewise, both hands are required to return the plier jaws to the nested storage position. This tends to limit the utility of the tool in some circumstances. In addition, when the handles are unfolded from the pliers, the open channel in which the pliers are received when in a folded position face outwardly. Thus, unless special provisions are made, typically involving the additional step of unfolding or pivoting a handle extension or sleeve, the open edges of the channel sides address the user's hand. This makes the pliers particularly uncomfortable to use.
Mechanisms for locking the handles of such tools in a particular position are also known. An example of such a locking mechanism is disclosed in the aforementioned U.S. Pat. No. 4,238,862 to Leatherman. However, such mechanisms typically must be specifically released before the handles can be further opened, and, thus, are not particularly suitable for maintaining the handles in a closed position when the pliers are stored or an ancillary tool is in use.
Although the tool disclosed in the Collins patent comprises pliers which are rotatably mounted in the recess of the handles and which may arguably be exposed in a single hand motion, the tool has other disadvantages. More specifically, this tool, having pliers designed for use in a range of positions at an angle from the handles as well as fully extended, do not allow locking of the pliers in operating position to prevent movement of the pliers with respect to the handles.